It has been well known that a carbostyryl derivative represented by the formula (1): ##STR1##
wherein R represents a tert-butyl group, or an acid addition salt thereof is a compound which is effective as a remedy for glaucoma (U.S. Pat. No. 4,309,432). The compound represented by the above formula (1) is referred to as carteolol.
On the other hand, an eye drop or an ophthalmic ointment is often used as the eye drop.
In case of the eye drop, since a base is usually purified water, it is difficult to adhere the eye drop onto the cornea in the case of dropping it in the eyes. Furthermore, it is impossible to avoid that the eye drop is diluted with lacrimal fluid and falls from the eyes. Accordingly, it was difficult for a conventional eye drop to sufficiently retain a drug in the eye drop in the eyes.
Furthermore, the ophthalmic ointment is prepared by adding liquid paraffin, purified lanolin or the like to petrolatum as a base. Such an ophthalmic ointment is liable to be discharged from the eyes by means of lacrimal fluid because of its poor hydrophilicity. Therefore, there is such a drawback that the opthalimic ointment is not sufficiently adhered onto the cornea and ophthalmic mucosa and, as a result, the amount of the drug in the ophthalmic ointment, which arrives the affected part and is absorbed, is small. The ophthalmic ointment also has a drawback that an unpleasant feel arises in the eyes after applying it because of oiliness of an oily base.
To solve the above drawbacks of the conventional eye drop and ophthalmic ointment, British Patent No. 2,007,091 corresponding to Japanese Patent Laid-Open Publication No. 67021/1979 suggests a gelled eye drop. The gelled eye drop described in said publication is an eye drop prepared by mixing an aqueous crosslinked type polyacrylic acid solution with a water-soluble basic substance and a drug for eye drop, which has the pH of 5 to 8 and the viscosity of 1,000 to 100,000 centipoise at 20.degree. C.
However, such a gelled eye drop is insufficient in duration time of drug efficacy, and is inferior in intraocular pressure inhibition action. Furthermore, the gelled eye drop is also insufficient in ease of handling and affinity to the eyes (feeling in the case of dropping it in the eyes). Accordingly, it is difficult to use such a gelled eye drop as an eye drop which is particularly effective for treatment of glaucoma requiring the control of the intraocular pressure.